NOAA National Weather Service Weather Forecast Office

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Severe weather in the form of a tornado, damaging straight-line
downburst winds, large hail, and flash flooding hammered a small
piece of south-central and much of southeast Wisconsin during the
late afternoon and evening hours.  The most significant cluster of
thunderstorms developed over southern Columbia county and proceded to
move east/southeast through Dodge, Jefferson, Waukesha, Milwaukee,
and Racine counties. A supercell on the west end of this cluster,
with a well-defined mesocyclone, produced some damaging straight-line
winds and large hail up to 2.25 inches in diameter in Jefferson
County, but could only generate a rotating wall cloud at its base in
that county.  This supercell continued to dump large hail as it moved
across Waukesha County, but once it moved over the city of Franklin
in southwestern Milwaukee County, it spawned a tornado at 1730CST
about 3/4 of a mile northwest of the intersection of Highways 41 and
100 (27th St. & Ryan Rd, or about 5.4 miles southwest of Milwaukee's
General Mitchell International Airport). This tornado tore
east/southeast through Oak Creek, and then exited Milwaukee County at
706 pm, where Highway 32 goes south into Racine County (or about 7
miles south/southeast of Mitchell Field).  The tornado continued for
about .2 miles into Racine County, just east of Highway 32, before
dissipating about 2.9 miles northeast of Husher.

Minor urban/small stream flooding affected parts of Waukesha and
Racine Counties, as well as much of Milwaukee County after the 1st
round of storms moved through and dumped rainfall of 1 to 2 inches.
Water depths on roads were reported to be 6 to 12 inches.

As with previous episodes of severe weather across southern Wisconsin
during May and June, flash flooding occurred later in the evening on
July 2nd, as additional rounds of storms, some severe, moved across
the area.  Torrential downpours, sometimes reaching an inch or more
within 15 minutes, produced flash flooding across the southern half
of Milwaukee County, the area from Hartland and Waukesha to
Brookfield and Elm Grove in Waukesha County, and in/near the city of
Racine (Racine Co.).  Water depths on roads in these areas reached 1
to 4 feet.  The flood waters resulted in gravel shoulder washouts on
roads, structural damage to basements, damage to basement contents,
and culvert damage. In the city of Franklin (Milwaukee Co.), a home's
basement walls collapsed due to the pressure of the flood waters.
Most small streams and creeks in Waukesha, southern Milwaukee, and
eastern Racine County quickly exceeded flood stage by 1 to 2 feet due
to the intense rainfall.

The Root River in Franklin, the Root River Canal at Raymond (Racine
Co.), Oak Creek in South Milwaukee, and the Menomonee River in
Wauwatosa all crested between 2115CST on July 2nd and 0315CST the
next morning.  Homes and businesses near these locations sustained
the worst flood damage.  Collectively, the Milwaukee County flash
flooding damaged 6974 residential homes, 38 businesses, 1 utility
building, and 9 agricultural buildings.  About 600 acres of farm land
in southern Milwaukee County sustained crop damage.  In Racine
County, 429 residential buildings were damaged by flash flood waters,
and about 2800 acres of farm land had crop damage or soil erosion.

Urban/small stream flooding was reported in the city of Madison, in
Sullivan, and around Richmond (Walworth Co.) due to the heavy
rainfalls.  Water depths on roads were in the 6 to 18 inch range.
The Madison area picked up 1.5 to 2.5 inches of rainfall (Madison
Truax Field had 1.89" for the day), the Sullivan area picked up an
estimated 2.5 to 3.0 inches, and 3.7 inches fell in Richmond on the
2nd.  No flood damage was reported from these locations.

Two separate lightning strikes in Franklin started fires that damaged
a car and a home's garage.

Twenty-four hour rainfall amounts (mostly in the late afternoon and
evening hours on July 2nd) ending 0600CST on July 3rd across
southeast Wisconsin were impressive:
Waukesha County...7.00" in Elm Grove, 5.06" at Carroll College,
4.27"in Hartland
Milwaukee County...6.50" in Greenfield, 5.05" south side of
Milwaukee, 4.75" in West Allis, 4 to 6" in Franklin, 4.22" at
Milwaukee Mitchell International Airport
Racine County...5.76" at Raymond, 3.99" in the city of Racine

The 4.42 inches of rain recorded at Milwaukee General Mitchell
International Airport on July 2nd, set a new record for the day and a
new daily record for any day in July.  This was also the 6th wettest
day for Milwaukee going back to the start of documentation in 1871.
Milwaukee would finish the month of July 2000 with 7.12 inches of
rain, the 3rd wettest July on record.

Synoptically, an old frontal boundary sagged south across southern
Wisconsin as low pressure moved east along it. A short-wave aloft was
also moving east across the region. Moist, unstable air, drawn north
into the frontal boundary, fueled the storms.